Integrated optics beam deflectors and systems

ABSTRACT

This invention discloses a method of aligning a multiplicity of waveguides with respect to external optics.

FIELD OF THE INVENTION

[0001] The present invention relates to integrated optics beamdeflectors and to systems, such as scanners and optical switches,employing such deflectors.

BACKGROUND OF THE INVENTION

[0002] Various types of integrated optics beam deflectors are known inthe art. U.S. Pat. No. 5,239,598, the disclosure of which is herebyincorporated by reference, and the references cited therein, as well asthe following articles are believed to represent the state of the art:

[0003] Katz et al, Phase-locked semiconductor laser array with separatecontacts, Appl. Phys. Lett 43, 1983, pp 521-523;

[0004] Vasey et al, Spatial optical beam steering with an AlGaAsintegrated phased array, Applied Optics, 32, No. 18, 20 June, 1993, pp3220-3232.

SUMMARY OF THE INVENTION

[0005] The present invention seeks to provide an improved light beamdeflector and systems employing same.

[0006] There is thus provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including:

[0007] at least one substrate having formed thereon a multiplicity ofwaveguides, each waveguide receiving light and emitting light, thetotality of light emitted by the multiplicity of waveguides producing atleast one selectably directable output beam; and

[0008] at least one sequential multiplexer applying electrical inputs tothe at least one substrate for individually controlling the lightemitted by each of the multiplicity of waveguides, thereby governing theorientation of the selectably directable output beam.

[0009] Preferably, the at least one sequential multiplexer is a phasecontroller which controls the phase of the light emitted by each of themultiplicity of waveguides.

[0010] Alternatively or additionally, the at least one sequentialmultiplexer is an intensity controller which controls the intensity ofthe light emitted by each of the multiplicity of waveguides.

[0011] In accordance with a preferred embodiment of the presentinvention, the at least one substrate includes a plurality ofsubstrates, each having formed thereon a multiplicity of waveguides,each waveguide receiving light and emitting light and wherein the atleast one sequential multiplexer applies electrical inputs to theplurality of substrates.

[0012] There is also provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including:

[0013] a plurality of substrates, each having formed thereon amultiplicity of waveguides, each waveguide receiving light and emittinglight, the totality of light emitted by the multiplicity of waveguidesproducing at least one selectably directable output beam.

[0014] Further in accordance with a preferred embodiment of the presentinvention there is provided a selectably directable optical beamgenerating device including:

[0015] a light source;

[0016] at least one substrate having formed thereon a multiplicity ofwaveguides, each waveguide receiving light from the light source andemitting light, the totality of light emitted by the multiplicity ofwaveguides producing at least one selectably directable output beam; and

[0017] Preferably the light source includes a laser formed on the atleast one substrate.

[0018] at least one sequential multiplexer applying electrical inputs tothe at least one substrate for individually controlling the lightemitted by each of the multiplicity of waveguides, thereby governing theorientation of the selectably directable output beam.

[0019] Preferably, the at least one sequential multiplexer is a phasecontroller which controls the phase of the light emitted by each of themultiplicity of waveguides.

[0020] Alternatively or additionally, the at least one sequentialmultiplexer is an intensity controller which controls the intensity ofthe light emitted by each of the multiplicity of waveguides.

[0021] Preferably, the at least one substrate includes a plurality ofsubstrates, each having formed thereon a multiplicity of waveguides,each waveguide receiving light and emitting light and wherein the atleast one sequential multiplexer applies electrical inputs to theplurality of substrates.

[0022] Additionally in accordance with a preferred embodiment of thepresent invention there is provided a selectably directable optical beamgenerating device including:

[0023] at least one light source; and

[0024] a plurality of substrates, each having formed thereon amultiplicity of waveguides, each waveguide receiving light from the atleast one light source and emitting light, the totality of light emittedby the multiplicity of waveguides producing at least one selectablydirectable output beam.

[0025] Still further in accordance with a preferred embodiment of thepresent invention there is provided a selectably directable optical beamdeflecting device including:

[0026] at least one substrate having formed thereon a multiplicity ofwaveguides; and

[0027] a microlens array receiving light and coupling the received lightto the multiplicity of waveguides.

[0028] Additionally in accordance with a preferred embodiment of thepresent invention there is provided a selectably directable optical beamgenerating device including:

[0029] a light source,

[0030] at least one substrate having formed thereon a multiplicity ofwaveguides; and

[0031] a microlens array receiving light from the light source andcoupling the received light to the multiplicity of waveguides.

[0032] There is also provided in accordance with another preferredembodiment of the present invention a selectably directable optical beamgenerating device including a light source, at least one substratehaving formed thereon a multiplicity of waveguides and a microlens arrayreceiving light from the light source and coupling the received light tothe multiplicity of waveguides.

[0033] Preferably the selectably directable optical beam generatingdevice provides wavelength division multiplexing.

[0034] There is also provided in accordance with another preferredembodiment of the present invention an optical device including at leastone substrate having formed thereon a multiplicity of polarizationindependent, electrically controlled waveguides, and a light receiverdirecting light into the multiplicity of waveguides.

[0035] Further in accordance with a preferred embodiment of the presentinvention each one of the multiplicity of polarization independent,electrically controlled waveguides includes first and second phaseshifting waveguide portions.

[0036] Still further in accordance with a preferred embodiment of thepresent invention the electric fields of different directions areapplied to the first and second phase shifting waveguide portions.

[0037] Preferably each of the multiplicity of polarization independentelectrically controlled waveguides includes first and secondphase-shifting waveguide portions of respective first and second lengthshaving respective first and second electric fields of differentdirections applied thereto.

[0038] Additionally in accordance with a preferred embodiment of thepresent invention at least one of the multiplicity of polarizationindependent, electrically controlled waveguides includes first andsecond phase shifting waveguide portions separated by a quarter-waveplate, whereby light from the first waveguide portion passes through thequarter-wave plate prior to entering the second waveguide portion.

[0039] There is also provided in accordance with a preferred embodimentof the present invention an optical device including at least onesubstrate having formed thereon a multiplicity of electricallycontrolled waveguides, and a light receiver for directing light into themultiplicity of waveguides, the light receiver including a selectablepolarization rotator.

[0040] There is also provided in accordance with yet another preferredembodiment of the present invention an optical device including at leastone substrate having formed thereon a multiplicity of electricallycontrolled waveguides, and a polarization rotator for rotating thepolarization of light passing through the multiplicity of electricallycontrolled waveguides by 90 degrees or an odd integer multiple thereofFurther in accordance with a preferred embodiment of the presentinvention the polarization rotator operates by generating a magneticfield extending parallel to longitudinal axes of the multiplicity ofwaveguides.

[0041] Still further in a accordance with a preferred embodiment of thepresent invention the selectable polarization rotator is automaticallyoperative to rotate the polarization so as to provide an optimized lightoutput from the multiplicity of waveguides.

[0042] Additionally in accordance with a preferred embodiment of thepresent invention the selectable polarization rotator is responsive toan output of the multiplicity of waveguides.

[0043] Moreover in accordance with a preferred embodiment of the presentinvention the selectable polarization rotator is responsive to thepolarization of an input to the multiplicity of waveguides.

[0044] Further in accordance with a preferred embodiment of the presentinvention and having selectably directable beam deflectionfunctionality. Alternatvely, the selectably directable beam deflectionfunctionality includes directable beam receiving functionality.

[0045] Further in accordance with a preferred embodiment of the presentinvention and the selectably directable functionality is realized bymeans of phase-shifting.

[0046] There is also provided in accordance with yet another preferredembodiment of the present invention an optical device including at leastone substrate having formed thereon a multiplicity of electricallycontrolled waveguides, and a light receiver directing light into themultiplicity of waveguides and including polarization maintainingoptical fibers.

[0047] There is also provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including at least one substrate having formed thereon amultiplicity of phase-shifting waveguides, and a light receiverdirecting light into the multiplicity of waveguides, and wherein the atleast one substrate includes multiple mutually insulated conductorlayers including a multiplicity of conductors, at least some of whichare connected to the waveguides by vias.

[0048] There is provided in accordance with another preferred embodimentof the present invention a selectably directable optical beam generatingdevice including at least one substrate having formed thereon amultiplicity of waveguides, and a laser monolithically formed on the atleast one substrate and providing light to the multiplicity ofwaveguides.

[0049] There is provided in accordance with a preferred embodiment ofthe present invention an optical device including at least one substratehaving formed thereon a multiplicity of waveguides, and a lasermonolithically formed on the at least one substrate and providing lightto the multiplicity of waveguides, the multiplicity of waveguides andthe laser being formed at different regions of identical layers.

[0050] There is provided in accordance with yet another preferredembodiment of the present invention a semiconductor laser including anN-doped gallium arsenide substrate, an N-doped aluminum gallium arsenidelayer formed over the substrate, an N-doped gallium arsenide layerformed over the N-doped aluminum gallium arsenide layer, a P-dopedgallium arsenide layer formed over the N-doped gallium arsenide layer, aP-doped aluminum gallium arsenide layer formed over the P-doped galliumarsenide layer, and a P-doped gallium arsenide layer formed over theP-doped aluminum gallium arsenide layer.

[0051] There is provided in accordance with a preferred embodiment ofthe present invention a selectably directable optical beam deflectingdevice including at least one substrate having formed thereon amultiplicity of waveguides, and a light receiver coupling light to themultiplicity of waveguides at first ends thereof, and wherein themultiplicity of waveguides are outwardly tapered at the first endsthereof There is also provided in accordance with yet another preferredembodiment of the present invention a selectably directable optical beamdeflecting device including at least one substrate having formed thereona multiplicity of waveguides, and a light receiver directing light intothe multiplicity of waveguides, the light receiver including acylindrical lens.

[0052] There is also provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including at least one substrate having formed thereon amultiplicity of waveguides, and a light receiver directing light intothe multiplicity of waveguides, the light receiver including amulti-mode interference coupler.

[0053] There is also provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including at least one substrate having formed thereon amultiplicity of waveguides, and a light receiver directing light intothe multiplicity of waveguides, the light receiver including a planarwave guide.

[0054] Further in accordance with a preferred embodiment of the presentinvention the multiplicity of waveguides have first ends which abut theplanar waveguide, the first ends being tapered outwardly.

[0055] Still further in accordance with a preferred embodiment of thepresent invention the multi-mode interference coupler includes a lightreceiving waveguide. Preferably the light receiving waveguide includes alight receiving end which is outwardly tapered.

[0056] Additionally in a accordance with a preferred embodiment of thepresent invention the light receiving waveguide includes anelectro-absorption modulator.

[0057] Moreover in accordance with a preferred embodiment of the presentinvention the electro-absorption modulator receives a modulating inputfrom a light detector monolithically formed therewith on the at leastone substrate.

[0058] Additionally or alternatively the multiplicity of waveguides iscontrollable so as to selectably provide multiple selectably directedoutput beams.

[0059] There is also provided in accordance with a preferred embodimentof the present invention a selectably directable optical beam deflectingdevice including at least one substrate having formed thereon amultiplicity of waveguides, and a light receiver directing light intothe multiplicity of waveguides, and wherein the multiplicity ofwaveguides is controllable so as to selectably provide multipleselectably directed output beams.

[0060] Additionally or alternatively the optical device also includes awaveguide filter including a necked waveguide having a relatively broadinput end which receives light and allows propagation of multi-modelight waves therethrough, a narrowed neck portion at which higher modesradiate outside the waveguide and only the modes which can propagatetherethrough pass therethrough, and a relatively broad output end.

[0061] There is also provided in accordance with a preferred embodimentof the present invention a waveguide filter including a necked waveguidehaving a relatively broad input end which receives light and allowspropagation of multi-mode light waves therethrough, a narrowed neckportion at which higher modes radiate outside the waveguide and only themodes which can propagate therethrough pass therethrough, and arelatively broad output end.

[0062] Preferably the optical device is implemented on gallium arsenide.

[0063] There is also provided in accordance with a preferred embodimentof the present invention an optical switch including a monolithicplurality of selectably directable optical beam deflecting devices, aplurality of optical beam receiving devices.

[0064] There is also provided in accordance with yet another preferredembodiment of the present invention an optical switch including aplurality of monolithic pluralities of selectably directable opticalbeam deflecting devices, a plurality of optical beam receiving devices.

[0065] Further in accordance with a preferred embodiment of the presentinvention the plurality of monolithic pluralities of beam deflectingdevices are arranged generally parallel to one another along an axisperpendicular to a plane in which selectable deflection of a light beamis produced thereby.

[0066] Still further in accordance with a preferred embodiment of thepresent invention the plurality of monolithic pluralities of beamdeflecting devices are arranged generally distributed along a curveextending in a plane perpendicular to a plane in which selectabledeflection of a light beam is produced thereby.

[0067] There is also provided in accordance with yet another preferredembodiment of the present invention an optical switch including aplurality of selectably directable optical beam deflecting devices, eachincluding at least one substrate having formed thereon a multiplicity ofwaveguides, and a plurality of optical beam receiving devices.

[0068] Further in accordance with a preferred embodiment of the presentinvention each of the plurality of optical beam receiving devicesincludes an optical fiber. Preferably the optical fiber has a numericalaperture of less than 0.3.

[0069] Additionally in accordance with a preferred embodiment of thepresent invention the selectably directable optical beam deflectingdevices each include at least one substrate having formed thereon amultiplicity of waveguides.

[0070] There is also provided in accordance with a preferred embodimentof the present invention an optical switch including a plurality ofoptical beam emitting devices and a monolithic plurality of selectablydirectable optical beam receiving devices. Preferably the optical beamreceiving devices are selectably directable.

[0071] There is also provided in accordance with a preferred embodimentof the present invention an optical switch including a plurality ofoptical beam emitting devices and a plurality of monolithic pluralitiesof selectably directable optical beam receiving devices.

[0072] Further in accordance with a preferred embodiment of the presentinvention the plurality of monolithic pluralities of beam receivingdevices are arranged generally parallel to one another along an axisperpendicular to a plane in which selectable deflection of a light beamis produced thereby. Alternatively the plurality of monolithicpluralities of beam receiving devices are arranged generally distributedalong a curve extending in a plane perpendicular to a plane in whichselectable deflection of a light beam is produced thereby.

[0073] Still further in accordance with a preferred embodiment of thepresent invention the selectable directable optical beam receivingdevices each include at least one substrate having formed thereon amultiplicity of waveguides.

[0074] There is also provided in accordance with a preferred embodimentof the present invention an optical switch including a plurality ofoptical beam emitting devices, and a plurality of selectably directableoptical beam receiving devices, each including at least one substratehaving formed thereon a multiplicity of waveguides.

[0075] Additionally in accordance with a preferred embodiment of thepresent invention both the optical beam emitting devices and the opticalbeam receiving devices are selectably directable.

[0076] Moreover in accordance with a preferred embodiment of the presentinvention and including a light input coupler to the plurality ofoptical beam devices and a cylindrical lens light output couplerreceiving light from the plurality of optical beam devices. Preferablythe cylindrical lens light output coupler includes a plurality ofcylindrical lenses, each associated with an optical beam device.Alternatively the cylindrical lens light output coupler includes asingle cylindrical lens associated with a plurality of optical beamdevices.

[0077] Additionally in accordance with a preferred embodiment of thepresent invention and including a light input coupler to the pluralityof optical beam devices which includes at least one cylindrical lens.Preferably the light input coupler to the plurality of optical beamdevices includes at least one cylindrical lens.

[0078] Moreover in accordance with a preferred embodiment of the presentinvention the at least one cylindrical lens includes a plurality ofcylindrical lenses, each associated with an optical beam device.

[0079] Still further in accordance with a preferred embodiment of thepresent invention the at least one cylindrical lens includes a singlecylindrical lens associated with a plurality of optical beam devices.

[0080] Further in accordance with a preferred embodiment of the presentinvention the light input coupler also includes a multiplicity ofmicrolenses fixed with respect to the at least one cylindrical lens,each of the multiplicity of microlenses directing light into a singlebeam transmitting device.

[0081] Preferably the multiplicity of microlenses includes focusingmicrolenses. Alternatively the multiplicity of microlenses includescollimating microlenses.

[0082] There is also provided in accordance with a preferred embodimentof the present invention an active optical beam transmission deviceincluding at least one substrate having formed thereon a multiple layerintegrated electronic circuit, and a multiplicity of electricallycontrolled waveguides.

[0083] Further in accordance with a preferred embodiment of the presentinvention the waveguides emit a selectably directable beam of light.Alternatively or additionally the waveguides selectably receive a beamof light.

[0084] Still further in accordance with a preferred embodiment of thepresent invention the multiplicity of waveguides are operativesimultaneously to deflect a plurality of optical beams.

[0085] Preferably overlying the waveguides, a multiplicity of electricalcontacts, each contact providing an electrical connection to at leastone of the multiplicity of electrically controlled waveguides.

[0086] There is also provided in accordance with a preferred embodimentof the present invention an active optical beam transmission deviceincluding at least one substrate having formed thereon a plurality ofwaveguide assemblies, each including a multiplicity of electricallycontrolled waveguides, and overlying each of the waveguide assemblies, amultiplicity of electrical contacts, each contact providing anelectrical connection to at least one of the multiplicity ofelectrically controlled waveguides in the assembly.

[0087] There is also provided in accordance with a preferred embodimentof the present invention a monolithic optical light modulator includinga substrate having formed monolithically thereon an electro-absorptionmodulator, and a light detector providing a modulating output to theelectro-absorption modulator.

[0088] There is also provided in accordance with a preferred embodimentof the present invention an optical waveguide-lens including at leastone substrate having formed thereon a multiplicity of electricallycontrolled, phase-shifting waveguides, and an electrical control signalsource providing electrical signals to the multiplicity of waveguides tocause them to have a desired lens functionality.

[0089] Additionally the optical devies described hereinabove may alsoinclude an electrical control signal source providing electrical signalsto the multiplicity of waveguides to cause them to have a desired lensfunctionality. Furthermore the optical devices may also include afeedback connection between the optical beam receiving devices and theoptical beam deflecting devices.

[0090] Still further in accordance with a preferred embodiment of thepresent invention the optical beam receiving devices are configured toreceive light over a region sufficiently large such that wavelengthdependencies of the deflectors do not substantially affect the amount oflight sensed by the receiving devices.

[0091] There is also provided in accordance with a preferred embodimentof the present invention an optical switch including a plurality ofselectably directable optical beam deflecting devices, a plurality ofoptical beam receiving devices, and wherein the plurality of selectablydirectable optical beam deflecting devices and the plurality of opticalbeam receiving devices are monolithically formed on the same substrate.

[0092] Further in accordance with a preferred embodiment of the presentinvention the plurality of selectably directable optical beam deflectingdevices and the plurality of optical beam receiving devices aremonolithically formed on the same substrate There is also provided inaccordance with a preferred embodiment of the present invention a methodof forming a monolithic structure having electrical contacts includingthe steps of configuring regions on a wafer such that upper and lowersurfaces are defined thereon, coating the upper and lower surfaces withmetal by evaporation in a direction generally perpendicular to the upperand lower surfaces, the direction being selected with respect tointerconnecting surfaces which interconnect the upper and lower surfacessuch that metal is not substantially coated onto the interconnectingsurfaces, whereby electrical connections between the upper and lowersurfaces via the interconnecting surfaces are not formed by the metalcoating.

[0093] Further in accordance with a preferred embodiment of the presentinvention the monolithic structure includes a waveguide device.

[0094] There is also provided in accordance with yet another preferredembodiment of the present invention a method for aligning a waveguidedevice including providing a waveguide having light emitting capability,and operating the waveguide to emit light during alignment thereof Thereis also provided in accordance with a preferred embodiment of thepresent invention an optical switch including a plurality of ports, anoptical crossbar assembly, and a plurality of information carryingoptical fibers interconnecting the plurality of ports with inputs to theoptical crossbar assembly, the information carrying optical fibersincluding polarization maintaining fibers.

[0095] There is also provided in accordance with yet another preferredembodiment of the present invention an optical switch including aplurality of ports, an optical crossbar assembly, and a plurality ofinformation carrying optical fibers interconnecting the plurality ofports with inputs to the optical crossbar assembly, the plurality ofports each having an input and output which are clock synchronized.

[0096] Additionally in a accordance with a preferred embodiment of thepresent invention the plurality of ports are clock synchronized amongthemselves.

BRIEF DESCRIPTION OF THE DRAWINGS

[0097] The present invention will be understood and appreciated morefully from the following detailed description, taken in conjunction withthe drawings in which:

[0098]FIG. 1 is a simplified illustration of laser writing apparatusconstructed and operative in accordance with a preferred embodiment ofthe present invention;

[0099]FIG. 2 is a simplified illustration of a scanning engine suitablefor use in the laser writing apparatus of FIG. 1;

[0100]FIGS. 3A and 3B illustrate two alternative embodiments of anintegrated optics scanning unit forming part of the scanning engine ofFIG. 2;

[0101]FIG. 4 is a simplified illustration of optical switching apparatusconstructed and operative in accordance with a preferred embodiment ofthe present invention;

[0102]FIG. 5 is a simplified illustration of an optical cross-connectassembly suitable for use in the optical switching apparatus of FIG. 4;

[0103]FIGS. 6A and 6B illustrate two alternative embodiments of anintegrated optics switching unit forming part of the cross-connectassembly of FIG. 5;

[0104]FIG. 7 is a simplified pictorial illustration of an integratedoptics beam deflection unit useful as part of an integrated opticsscanning unit of the type shown in FIGS. 3A and 3B or as part of anintegrated optics switching unit of the type shown in FIG. 6A or 6B;

[0105]FIGS. 8A and 8B illustrate a waveguide unit useful as part of theintegrated optics beam deflection unit of FIG. 7;

[0106]FIGS. 9A, 9B, 9C and 9D are graphs illustrating the far-fielddiffraction pattern produced by an optical beam deflector constructedand operative in accordance with a preferred embodiment of the presentinvention for different applied voltages;

[0107]FIG. 10 is a simplified illustration of a multiplexer providingsequential voltage inputs to multiple waveguides forming part of a beamdeflection unit in accordance with a preferred embodiment of the presentinvention;

[0108]FIG. 11 is a graph illustrating the wavelength dependency of theangular location of diffraction produced in accordance with a preferredembodiment of the present invention;

[0109]FIG. 12 is a simplified illustration of wave division multiplexingapparatus constructed and operative in accordance with a preferredembodiment of the present invention;

[0110]FIG. 13 is a simplified flowchart illustrating the manufacture ofa waveguide device in accordance with a preferred embodiment of thepresent invention;

[0111]FIGS. 14A, 14B, 14C, 14D and 14E are illustrations of variousstages in the manufacture of the waveguide device in accordance with thesteps set forth in FIG. 13;

[0112]FIG. 15 is a simplified illustration of a polarization-independentwaveguide constructed and operative in accordance with a preferredembodiment of the present invention;

[0113]FIGS. 16A, 16B and 16C are illustrations of the operationalparameters of the waveguide of FIG. 15;

[0114]FIG. 17 is a simplified illustration of a polarization-independentwaveguide constructed and operative in accordance with another preferredembodiment of the present invention;

[0115]FIG. 18 is a simplified illustration of a polarization-independentwaveguide constructed and operative in accordance with yet anotherpreferred embodiment of the present invention;

[0116]FIG. 19 is a simplified illustration of a polarization-independentwaveguide constructed and operative in accordance with still anotherpreferred embodiment of the present invention;

[0117]FIG. 20 is a simplified illustration of an optimal waveguidestructure for a given wavelength in accordance with a preferredembodiment of the present invention;

[0118]FIG. 21 is a simplified illustration of part of a waveguide devicehaving multiple conductors constructed and operative in accordance witha preferred embodiment of the present invention;

[0119]FIG. 22 is a simplified illustration of a monolithic laser andwaveguide structure constructed and operative in accordance with apreferred embodiment of the present invention;

[0120]FIG. 23 is a simplified illustration of part of a waveguide devicehaving tapered inputs;

[0121]FIG. 24 is a simplified illustration of a waveguide device havinga multi-mode interference coupler including a tapered input waveguide;

[0122]FIG. 25 is a simplified illustration of wave propagation in awaveguide device having a multi-mode interference coupler;

[0123]FIG. 26 is a simplified illustration of wave propagation in awaveguide device having a free-space input coupler;

[0124]FIG. 27 is a simplified illustration of an optical cross-connectassembly constructed and operative in accordance with a preferredembodiment of the present invention;

[0125]FIG. 28 is a simplified illustration of a monolithic device havingboth electronic and optical functionality;

[0126]FIG. 29 is a simplified illustration of part of an optical switchincluding a monolithic plurality of selectably directable optical beamdeflecting devices in accordance with one preferred embodiment of thepresent invention;

[0127]FIG. 30 is a simplified illustration of part of an optical switchincluding a monolithic plurality of selectably directable optical beamdeflecting devices in accordance with another preferred embodiment ofthe present invention;

[0128]FIG. 31 is a simplified illustration of part of an optical switchincluding a monolithic plurality of selectably directable optical beamdeflecting devices in accordance with yet another preferred embodimentof the present invention;

[0129]FIG. 32 is a simplified illustration of a waveguide device havinga light coupler including a modulator associated with an inputwaveguide;

[0130]FIG. 33 is a simplified illustration of a beam deflector includinga waveguide structure in accordance with a preferred embodiment of thepresent invention;

[0131]FIG. 34 is an illustration of operational parameters of awaveguide device having lens functionality in accordance with apreferred embodiment of the present invention;

[0132]FIG. 35 is a simplified illustration of part of an opticalcross-connect assembly constructed and operative in accordance with apreferred embodiment of the present invention;

[0133]FIG. 36 is a simplified illustration of an optical cross-connectassembly constructed and operative in accordance with another preferredembodiment of the present invention;

[0134]FIG. 37 is a simplified illustration of an optical cross-connectassembly constructed and operative in accordance with yet anotherpreferred embodiment of the present invention;

[0135]FIG. 38 is a simplified illustration of an optical cross-connectassembly of the type shown in any of FIGS. 35-37 with feedbackfunctionality;

[0136]FIG. 39 is a simplified illustration of an optical cross-connectassembly constructed and operative in accordance with a preferredembodiment of the present invention;

[0137]FIG. 40 is a simplified illustration of an optical cross-connectassembly constructed and operative in accordance with another preferredembodiment of the present invention;

[0138]FIG. 41 is a simplified illustration of a waveguide filterconstructed and operative in accordance with a preferred embodiment ofthe present invention; and

[0139]FIG. 42 is a simplified illustration of a monolithic opticalcross-connect assembly constructed and operative in accordance with apreferred embodiment of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0140] Reference is now made to FIG. 1, which is a simplifiedillustration of laser writing apparatus constructed and operative inaccordance with a preferred embodiment of the present invention. Thelaser writing apparatus typically comprises a laser scanning unit 20,illustrated in FIG. 2, which writes a latent image 21 onto aphotoreceptor 22, which is typically located on the cylindrical surfaceof a drum 23.

[0141] The photoreceptor 22, bearing the latent image 21, receives tonerfrom a toner hopper 24 via a developer roller 26 and transfers the toneronto a substrate 28 with the assistance of a transfer corotron 30. Thetoner is fused onto the substrate by a fuser 32. A discharge lamp 34serves to discharge the photoreceptor 22. Downstream of discharge lamp34, a charge corotron 36 uniformly charges the photoreceptor, upstreamof impingement thereon of laser beams 37 from laser scanning unit 20,which selectively discharges regions on the photoreceptor, thus creatingthe latent image 21.

[0142] It is a particular feature of the present invention that thelaser scanning unit 20, as illustrated in FIG. 2, comprises a selectablydirectable optical beam deflector including a base 50 onto which aremounted a plurality of substrates 52, each having formed thereon amultiplicity of waveguides 54, preferably 256 in number, each waveguide54 preferably receiving light and emitting light having a selectablephase, intensity or a combination thereof. The totality of light emittedby the multiplicity of waveguides 54 on each substrate 52 is supplied toan output lens 55, which produces a selectably directable output beam56, which covers a given sector of the photoconductor. The varioussubstrates cooperate to cover the entire useful area of thephotoconductor.

[0143] It is a particular feature of the present invention that thesubstrates 52 need not be aligned on base 50 to a very high degree ofaccuracy, inasmuch as the orientations of beams 56 produced thereby areelectronically determined and adjustable, inter alia to takemisalignment into account.

[0144] At least one sequential multiplexer 58 applies electrical inputsto each substrate 52 for individually controlling the light emitted byeach of the multiplicity of waveguides 54, thereby governing theorientation of said selectably directable output beam 56. Preferably,the sequential multiplexer 58 is a phase controller which controls thephase of the light emitted by each of the multiplicity of waveguides.Alternatively multiplexer 58 may be an intensity controller or acombination phase/intensity controller. Multiplexer 58 may be on asubstrate separate from or integral with substrate 52.

[0145] An input light source 60, such as a diode laser or an opticalfiber, provides a light beam 62 which impinges on an input lens assembly64, a preferred embodiment of which is illustrated in FIG. 7. The inputlens assembly 64 provides a multiplicity of focused beams 65, each ofwhich impinges on one of the waveguides 54 on substrate 52.

[0146] As seen in FIG. 7, the input lens assembly 64 typically comprisesa combination of a cylindrical lens 66 and an array of cylindricalmicrolenses 67 bonded thereto. The output lens 55 typically comprisesmutually perpendicularly aligned cylindrical lenses 68 and 69.

[0147] Reference is now made to FIGS. 3A and 3B, which illustrate twoalternative embodiments of an integrated optics scanning unit formingpart of the scanning engine of FIG. 2. In the embodiment of FIG. 3A, aninput laser 70, such as a diode laser, receives a laser control signalfrom content control electronics (not shown) and provides a laser beam72 which impinges on an input lens assembly 74, a preferred embodimentof which is illustrated in FIG. 7.

[0148] The input lens assembly 74 provides a multiplicity of focusedbeams 76, each of which impinges on one of the waveguides 54 onsubstrate 52. Each waveguide 54 receives an electrical input via acorresponding conductor 78, which extends from the waveguide to acorresponding connector pad 80 which is also formed on substrate 52. Asequential multiplexer 58 (FIG. 2), formed on a separate substrate 82receives address information via an address bus 84 and a phase,intensity, or phase/intensity input via an input line 86 from controlelectronics (not shown) and supplies a phase, intensity, orphase/intensity control signal to each waveguide 54 via a conductor 88and a corresponding connector pad 80 and conductor 78.

[0149] The phase, intensity or phase/intensity controlled outputs 90 ofeach of the waveguides 54 are combined in an output lens 92 and producea focused output beam 94, whose direction is controlled by the phase,intensity or phase/intensity inputs supplied via multiplexer 58.

[0150] The embodiment of FIG. 3B is identical to that of FIG. 3A otherthan in that multiplexer 58 (FIG. 2) is not embodied on a separatesubstrate from that on which the waveguides 54 are formed, as in FIG.3A. In the embodiment of FIG. 3B, waveguides 54 and sequentialmultiplexer 58 are both embodied on a single substrate 100 and thusconnector pads 80 may be eliminated. The remaining elements of FIG. 3Bmay be identical to those in FIG. 3A and are indicated by the samereference numerals.

[0151] According to an alternative embodiment of the present invention,input and output lenses 74 and 92 may be eliminated. Other types ofoptical couplers, known in the art, may be employed instead.

[0152] Reference is now made to FIG. 4, which is a simplifiedillustration of optical switching apparatus constructed and operative inaccordance with a preferred embodiment of the present invention. Theoptical switching apparatus preferably comprises an optical interconnectunit 10 which is connected to a multiplicity of ports 112, most or eachof which has a data output line 114, an address output line 116 and adata input line 118, as well as a, preferably duplex, informationconduit 120 which can be of any suitable form, such as, for example,copper or fiber and which can receive data in any suitable format. Someof the ports 112 may lack a data input line or may lack a data outputline and an address output line.

[0153] When optical fibers are employed as data output lines 114, it ispreferred that polarization maintaining fibers be employed inconjunction with polarized lasers or other polarized light sources. Thiseliminates polarization sensitivity of the beam deflection.

[0154] Preferably clock synchronization is maintained between the inputand output portions of each of ports 112 and between the various ports112.

[0155] The optical interconnect unit 110, a preferred embodiment ofwhich is illustrated in FIG. 5, comprises a beam deflector assemblyarray 122 and a beam receiving assembly array 124. Each beam deflectorassembly in array 122 receives data and address inputs from a port 112and each beam receiving assembly in array 124 provides a data input to aport 112.

[0156] It is a particular feature of the present invention that theoptical interconnect unit 110, as illustrated in FIG. 5, comprises aselectably directable optical beam deflector including a base 150 ontowhich are mounted a plurality of substrates 152, each having formedthereon a multiplicity of waveguides 154, preferably 256 in number, eachwaveguide 154 preferably receiving light and emitting light having aselectable phase. The totality of light emitted by the multiplicity ofwaveguides 154 on each substrate 152 produces a selectably directableoutput beam 156.

[0157] Also preferably mounted on base 150 is the beam receivingassembly array 124. Each beam receiving assembly 158 preferablycomprises a beam receiving lens 160 which couples a received beam ontoan output fiber 162, which is preferably a flexible fiber.Alternatively, the output fiber 162 may be replaced by a suitable lightdetector.

[0158] It is a particular feature of the present invention that thesubstrates 152 and the beam receiving assemblies 158 need not be alignedon base 150 to a very high degree of accuracy, inasmuch as theorientations of beams 156 produced thereby is electronically determinedand adjustable, inter alia to take into misalignment into account.

[0159] At least one sequential multiplexer 168 applies electrical inputsto each substrate 152 for individually controlling the light emitted byeach of the multiplicity of waveguides 154, thereby governing theorientation of the selectably directable output beam 156.

[0160] Preferably, the sequential multiplexer 168 is a phase controllerwhich controls the phase of the light emitted by each of themultiplicity of waveguides. Alternatively, multiplexer 168 is anintensity or phase/intensity controller.

[0161] Reference is now made to FIGS. 6A and 6B, which illustrate twoalternative embodiments of an integrated optics switching unit formingpart of the cross-connect assembly of FIG. 5. In the embodiment of FIG.6A, an input optical fiber 170 provides a beam 172 which impinges on aninput lens assembly 174, a preferred embodiment of which is illustratedin FIG. 7.

[0162] The input lens assembly 174 provides a multiplicity of focusedbeams 176, each of which impinges on one of the waveguides 154 onsubstrate 152. Each waveguide 154 receives an electrical input via acorresponding conductor 178, which extends from the waveguide to acorresponding connector pad 180 which is also formed on substrate 152. Asequential multiplexer 168 (FIG. 5), formed on a separate substrate 182,receives address information via an address bus 184 and a phase,intensity or phase/intensity input via an input line 186 from controlelectronics (not shown) and supplies a phase, intensity orphase/intensity control signal to each waveguide 154 via a conductor 188and a corresponding connector pad 180 and conductor 178.

[0163] The phase, intensity or phase/intensity controlled outputs 190 ofeach of the waveguides 154 are combined in an output lens 192 andproduce a focused output beam 194, whose direction is controlled by thephase, intensity or phase/intensity inputs supplied via multiplexer 168.

[0164] The embodiment of FIG. 6B is identical to that of FIG. 6A otherthan in that sequential multiplexer 168 (FIG. 5) is not embodied on aseparate substrate from that on which the waveguides 154 are formed, asin FIG. 6A. In the embodiment of FIG. 6B, waveguides 154 and sequentialmultiplexer 168 are both embodied on a single substrate 200 and thusconnector pads 180 may be eliminated. The remaining elements of FIG. 6Bmay be identical to those in FIG. 6A and are indicated by the samereference numerals.

[0165] Reference is now made to FIGS. 8A and 8B. FIG. 8A is aperspective illustration of a waveguide unit useful as part of theintegrated optics beam deflection unit of FIG. 7, while FIG. 8B is adetailed sectional illustration of a pair of waveguides forming part ofthe waveguide unit of FIG. 8A. It is seen from a consideration of FIGS.8A and 8B that substrate 52 (FIGS. 2 & 7) is preferably formed of an Ndoped GaAs layer 250 having formed on the bottom thereof an N-type ohmiccontact 252, typically comprising evaporated Ni/GeAu/Ni/Au. Formed overlayer 250 is a cladding layer 254, preferably formed of N doped AlGaAs.

[0166] The waveguide 54 is based on layer 254 and includes a core layer256 comprising a GaAs PN junction defined by an N layer 258 and a Player 260. A cladding layer 262, preferably formed of P doped AlGaAs, ispreferably formed over layer 260. A cap layer 264, preferably formed ofP+ doped GaAs, is preferably formed over layer 262.

[0167] Along the length of the waveguides there are provided P-typeohmic contacts 266, typically formed of Ti/Au. Adjacent waveguides 54are separated from each other by etching. The resultant gaps areindicated by reference numeral 268.

[0168] A polyimide insulative layer 270 is preferably formed over layer266, fills gaps 268, and defines intermittent discrete apertures 272.Intermitted strips of a metal layer 274 are formed over the polyimideinsulative layer 270 and contact the ohmic contacts 266 through discreteapertures 272 in the polyimide layer 270. The intermittent stripsprovide individual mutually insulated electrical pathways communicatingwith each of the waveguides 54 separately. These pathways are designatedby reference numeral 78 in FIGS. 3A and 3B and by reference numeral 178in FIGS. 6A and 6B.

[0169] It is appreciated that the depth of gaps 268 defined by etchingmay vary such that layers 250, 254, 258 and 260 may or may not be etchedto define gaps and waveguides. It is to be appreciated that waveguides54 may also be provided by any other suitable technique, such as, forexample, ion implantation.

[0170] Waveguide structures of this general type are described in thefollowing publication, and the references cited therein, the disclosuresof which are hereby incorporated by reference:

[0171] J. G. Mendoza-Alvarez et al, Analysis of Depletion EdgeTranslation Lightwave Modulators, IEEE Journal of Lightwave TechnologyVol. 6, No. 6, June 1988, pp. 793-808.

[0172] Reference is now made to FIGS. 9A, 9B, 9C and 9D, which aregraphs illustrating a simulation of the far-field diffraction andinterference pattern produced by an optical beam deflector constructedand operative in accordance with a preferred embodiment of the presentinvention for different applied voltages. The simulation is for anoptical beam deflector which includes 256 waveguides having a pitchbetween adjacent waveguides of 9 microns. The width of each waveguide is3 microns and the wavelength of the light passing through the deflectoris 1.3 microns.

[0173]FIGS. 9A, 9B, 9C and 9D illustrate the far-field diffraction andinterference patterns for phase shifts between adjacent waveguides of 0;π/2; π; and 3π/2, respectively.

[0174] It can be seen from a consideration of FIGS. 9A-9D that therelative phase of each of the waveguides determines the angular locationof given lobes of the interference pattern, while the diffractionpattern defines an intensity envelope which does not vary with phase butcauses different angular locations to have different intensities.

[0175] It is a particular feature of the present invention that theratio between the angular width of each of the lobes and the angularseparation between adjacent lobes is very substantial, due to the factthat the invention enables a very large number of waveguides (typically256) to be formed on a substrate and individually operated.

[0176] This high ratio enables a correspondingly high level ofresolution to be realized in various applications, such as scanning andswitching, providing a high number of individually addressable scanningand switching locations.

[0177] It may also be appreciated by persons skilled in the art that thepeak signal to background ratio is very high due to large number ofwaveguides employed.

[0178] Reference is now made to FIG. 10 which is an illustration of anoptical multiplexer providing sequential voltage inputs to multiplewaveguides forming part of a beam deflection unit in accordance with apreferred embodiment of the present invention.

[0179] As seen in FIG. 10, each waveguide 54 intermittently receives anelectrical input via an electrical pathway, such as pathway 78 (FIGS. 3Aand 3B) or 178 (FIGS. 6A and 6B). The electrical input is preferablysupplied from the drain 301 of a FET transistor 300 whose gate 302 iscoupled to the output of an AND gate 304. The source of each FETtransistor 300 receives a phase, intensity or phase/intensity input froman analog voltage line 306, identified by reference numeral 86 in FIGS.3A and 3B and by reference numeral 186 in FIGS. 6A and 6B.

[0180] Each AND gate 304 receives a plurality of digital address inputsvia NOT gates 308 from an address bus 310, which is identified byreference numeral 84 in FIGS. 3A and 3B and by reference numeral 184 inFIGS. 6A and 6B. Each AND gate 304 is differently configured such thatevery available combination of address inputs causes a different singleAND gate to provide an electrical output to a corresponding gate of acorresponding FET transistor 300.

[0181] It is a particular feature of the present invention that themultiplexer sequentially provides individual phase, intensity orphase/intensity inputs to the individual waveguides, using digitaladdress coding, thus enabling a very large number of waveguides to beindividually addressed.

[0182] Reference is now made to FIG. 11, which illustrates thewavelength dependency of the angular location of the diffraction orders.This wavelength dependency may be employed advantageously in accordancewith a preferred embodiment of the present invention to providewavelength division multiplexing (WDM). In this manner multipleinformation channels may be sent over a single physical fiber bytransmitting each channel along a separate wavelength.

[0183] Reference is now made to FIG. 12, which illustrates wavelengthdivision multiplexing apparatus constructed and operative in accordancewith a preferred embodiment of the present invention.

[0184] The wavelength division multiplexing apparatus 410 preferablycomprises a beam diffractor assembly array 422 and a beam receivingassembly array 424. Each beam diffractor assembly in array 422 receivesdata and address inputs from a port and produces a light beam havingmultiple wavelength components and each beam receiving assembly in array424 provides a data input to a port.

[0185] It is a particular feature of the present invention that thewavelength division multiplexing unit 410, as illustrated in FIG. 12,comprises an optical beam diffractor, which preferably also operates asa selectably directable optical beam deflector and includes a base 450onto which are mounted a plurality of substrates 452, each having formedthereon a multiplicity of waveguides 454, preferably 256 in number, eachwaveguide 454 preferably receiving light and emitting light in aplurality of beams according to their wavelength. The totality of lightemitted by the multiplicity of waveguides 454 on each substrate 452preferably produces a plurality of selectably directable output beams,here indicated as beams 456 and 457.

[0186] Also preferably mounted on base 450 is the beam receivingassembly array 424. Each beam receiving assembly 458 preferablycomprises a beam receiving lens 460 which couples a received beam ontoan output fiber 462, which is preferably a flexible fiber.Alternatively, the output fiber 462 may be replaced by a suitable lightdetector. Each beam receiving assembly preferably receives a beam of adifferent wavelength.

[0187] It is a particular feature of the present invention that thesubstrates 452 and the beam receiving assemblies 458 need not be alignedon base 450 to a very high degree of accuracy, inasmuch as theorientations of beams 456 produced thereby is electronically determinedand adjustable, inter alia to take into misalignment into account.

[0188] Reference is now made to FIG. 13, which is a simplified flowchartillustrating the manufacture of a waveguide device of the type shown inFIG. 8B, in accordance with a preferred embodiment of the presentinvention. As indicated in FIG. 13 a multi-layer gallium arsenide wafer,such as that illustrated in FIG. 8B and including layers 250, 254, 258,260, 262 and 264, is coated with metal to provide a layer such as layer252 (FIG. 8B). This initial stage is illustrated in FIG. 14A, whereinthe wafer is designated by reference numeral 500 and the metal layer isillustrated by reference numeral 502.

[0189] The waveguiding regions of the waver, e.g. layers 258, 260, 262and 264 (FIG. 8B) are configured preferably by standard photolithographyand reactive ion etching. This stage is illustrated in FIG. 14B, wherethe waveguiding regions are indicated by reference numeral 504.

[0190] It is a particular feature of the invention that the front sideof the wafer, i.e. the top surfaces 506 of waveguiding regions 504 andthe top surfaces 508 of the recesses 510 therebetween, is selectivelycoated with metal by evaporation in a direction generally perpendicularthereto, the direction being selected with respect to interconnectingsurfaces 512 which interconnect the upper and lower surfaces 506 and 508respectively such that metal is not substantially coated onto theinterconnecting surfaces 512, whereby electrical connections between theupper and lower surfaces 506 and 508 via the interconnecting surfaces512 are not formed by the metal coating. The metal layer, which isdesignated by reference numeral 266 in FIG. 8B, is indicated byreference numeral 514 in FIG. 14C.

[0191] Following formation of 514 by evaporation as aforesaid, one ormore conductive layers, separated from each other and from metal layer514 by insulative layers, are preferably provided. A conductive layer isindicated in FIG. 8B by reference numeral 274 and in FIG. 14D byreference numeral 516 and an insulative layer is indicated in FIG. 8B byreference numeral 270 and in FIG. 14D by reference number 518. Vias 520are preferably provided to interconnect conductive layers, such as layer516, with layer 514 through insulative layer 518. As seen in FIG. 14E,the outlines of the monolithic device may then be defined by cleavingand dicing.

[0192] Reference is now made to FIG. 15, which is a simplifiedillustration of a polarization-independent waveguide constructed andoperative in accordance with a preferred embodiment of the presentinvention. The waveguide of FIG. 15 is characterized in that it isformed of at least two elongate portions 530 and 532, separated by a gap534. Gap 534 is preferably smaller than the wavelength of the lightguided by the waveguide. A DC voltage V1 of a first polarity is appliedto elongate portion 530, while a DC voltage V2 of a second polarity,opposite to the first polarity, is applied to elongate portion 532. Gap534 need not be a cut or other physical separation, but may be only anelectrical or conductive separation.

[0193] It is known that the presence of an electric field in a galliumarsenide waveguide changes the phase of light passing through thewaveguide. The resulting change in phase differs with the polarizationof the light, whereby for a given electric field light of onepolarization, such as light in a TE mode is phase shifted more thanlight of polarization perpendicular thereto, such as light in a TM mode.

[0194] It has been appreciated by the present inventors that byswitching the direction of the electric field, the effect thereof onlight in the TE and TM modes is reversed. This can be seen from aconsideration of FIGS. 16A and 16B, which illustrate the phase shiftsproduced in mutually perpendicularly polarized light by electric fieldsof opposite polarity.

[0195] Thus, if an electric field in a first direction causes a greaterphase change for light in a TE mode than for light in a TM mode, anelectric field in a second direction, opposite to the first direction,causes a greater phase change for light in a TM mode than for light in aTE mode.

[0196] Accordingly, by first applying an electric field in a firstdirection to light guided along the waveguide and then applying anelectric field in a second direction, opposite to the first direction,to that light, the effect of polarization on the phase change of thelight is neutralized. This is visualized in FIG. 16C.

[0197] It is appreciated that the two electrical fields need notnecessarily be opposite in order to neutralize the effect ofpolarization as aforesaid. The desired neutralization may be realizedempirically even with electric fields which are not opposite.

[0198] Reference is now made to FIG. 17, which is a simplifiedillustration of a polarization-independent waveguide constructed andoperative in accordance with another preferred embodiment of the presentinvention. The waveguide of FIG. 17 is characterized in that it isformed of two elongate portions 550 and 552 of identical length,separated by a quarter wave plate 554. The quarter wave plate isoperative to rotate the polarization direction of light guided along thewaveguide by 90 degrees, therefore shifting the TM component to a TEcomponent and vice versa.

[0199] Thus light traveling along the entire waveguide has the samephase change irrespective of its polarization upon entry to thewaveguide.

[0200] Reference is now made to FIG. 18, which is a simplifiedillustration of a polarization-independent waveguide constructed andoperative in accordance with yet another preferred embodiment of thepresent invention. In this embodiment, there is provided a selectablydirectable optical beam deflecting device comprising a substrate 570having formed thereon a multiplicity of electrically controlled,phase-shifting waveguides 572, such as waveguides of the type describedhereinabove with reference to FIGS. 8A and 8B.

[0201] In accordance with a preferred embodiment of the presentinvention there is also formed on substrate 570 a light receiver 574 fordirecting light into the multiplicity of waveguides 572. Preferably, thelight receiver comprises a selectable polarization rotator 576. Inaccordance with a preferred embodiment of the present invention, theselectable polarization rotator is automatically operative to rotate thepolarization so as to provide an optimized light output from themultiplicity of waveguides.

[0202] Preferably, the selectable polarization rotator is responsive toan output of the multiplicity of waveguides. Alternatively, theselectable polarization rotator is responsive to the polarization of aninput to the multiplicity of waveguides.

[0203] The selectable polarization rotator is preferably embodied in agallium arsenide voltage controlled waveguide, which may be constructedin a manner similar or identical to that described hereinabove.

[0204] Reference is now made to FIG. 19, which is a simplifiedillustration of a polarization-independent waveguide constructed andoperative in accordance with still another preferred embodiment of thepresent invention. This embodiment is characterized in that apolarization rotator 590 rotates the polarization of light passingthrough a multiplicity of electrically controlled, phase-shiftingwaveguides 592 by 90 degrees. Preferably, the polarization rotator 590comprises a magnetic field source producing a magnetic field B, whoseaxis lies parallel to the longitudinal axes of the waveguides 592. Themagnetic field B is typically produced by the flow of an electriccurrent i, as shown in FIG. 19.

[0205] In this way, light guided along the waveguide has itspolarization shifted by 90 degrees, therefore shifting the TM componentto a TE component and vice versa.

[0206] Thus light traveling along the entire waveguide has the samephase change irrespective of its polarization upon entry to thewaveguide.

[0207] As in the embodiment of FIG. 18, in accordance with a preferredembodiment of the present invention, the selectable polarization rotator590 is automatically operative to rotate the polarization so as toprovide an optimized light output from the multiplicity of waveguides592.

[0208] Preferably, the selectable polarization rotator 590 is responsiveto an output of the multiplicity of waveguides 592. Alternatively, theselectable polarization rotator 590 is responsive to the polarization ofan input to the multiplicity of waveguides 592.

[0209] Reference is now made to FIG. 20, which is a simplifiedillustration of an optimal waveguide structure for a given wavelength inaccordance with a preferred embodiment of the present invention. FIG. 20illustrates an optimal distribution of light in the waveguide of FIG.8B. The light intensity is illustrated by trace 598. Preferably, thewaveguide is constructed such that most of the light is confined inlayers 256 (FIG. 8B). Little or no light is to be allowed in conductivelayers 266 and 252. Techniques for confining light in layers 256 arewell known in the art and need not be described herein.

[0210] It is additionally preferred that a P-N junction 600 be definedin layers 256 as indicated in FIG. 8B.

[0211] Reference is now made to FIG. 21, which is a simplifiedillustration of part of a waveguide device having multiple conductorsconstructed and operative in accordance with a preferred embodiment ofthe present invention. In the embodiment of FIG. 21, there is provided asubstrate 610 having formed thereon a multiplicity of phase-shiftingwaveguides 612. A light receiver (not shown) directs light into themultiplicity of waveguides. The substrate 610 comprises multiplemutually insulated conductor layers 614, which are insulated byinsulative layers 616 and are connected to said waveguides by vias 618.Vias 618 are constructed layer by layer and are interconnected via pads620.

[0212] Reference is now made to FIG. 22, which is a simplifiedillustration of part of a monolithic laser and waveguide structureconstructed and operative in accordance with a preferred embodiment ofthe present invention. Such monolithic structure are believed to benovel. The structure of FIG. 22 preferably comprises a substrate 620having formed thereon a multiplicity of waveguides 622, of which onlyone is shown, and a laser 624, monolithically formed on the substrate620 and providing light to the multiplicity of waveguides 622.

[0213] The laser 624 preferably is constructed in accordance with theforegoing description of FIG. 8B and includes:

[0214] an N-doped gallium arsenide substrate 626;

[0215] an N-doped aluminum gallium arsenide layer 628 formed oversubstrate 626;

[0216] an N-doped gallium arsenide layer 630 formed over the N-dopedaluminum gallium arsenide layer 628;

[0217] a P-doped gallium arsenide layer 632 formed over the N-dopedgallium arsenide layer 630;

[0218] a P-doped aluminum gallium arsenide layer 634 formed over theP-doped gallium arsenide layer 632; and

[0219] a P-doped gallium arsenide layer 636 formed over the P-dopedaluminum gallium arsenide layer 634.

[0220] It is a particular feature of the present invention that the factthat the waveguide structure of FIG. 8B can be operated as a lightsource, enables greatly enhanced ease of alignment of the waveguide withrespect to external optics, since the waveguide can produce a beam oflight during alignment thereof.

[0221] Reference is now made to FIG. 23, which is a simplifiedillustration of part of a waveguide device having tapered inputs. Thestructure of FIG. 23 can be used as part of a selectably directableoptical beam deflecting device and includes a substrate 650 havingformed thereon a multiplicity of waveguides 652 and a light receiver 654directing light into the multiplicity of waveguides at first endsthereof The structure is characterized particularly in that themultiplicity of waveguides 652 are outwardly tapered at said first endsthereof 656 at which light enters the waveguides. Preferably, the lightreceiver employs a cylindrical lens 658. It is appreciated that thestructure of FIG. 23 may be used as a light output structure and notonly as a light input structure.

[0222] Reference is now made to FIG. 24, which is a simplifiedillustration of a waveguide device having a multi-mode interferencecoupler including a tapered input waveguide. The structure of FIG. 24 isan alternative to the structure of FIG. 23 and includes a substrate 670having formed thereon a multiplicity of waveguides 672. Here a lightreceiver 674 comprising a multi-mode interference coupler 676 directslight into the multiplicity of waveguides 672.

[0223] Preferably, the multi-mode interference coupler comprises a lightreceiving waveguide 678 which includes a light receiving end 680 whichmay be outwardly tapered. Light which is received at light receiving end680 is typically coupled from an optical fiber 682. The optical fiber682 has preferably a matching output end 683 for coupling to thereceiving end 680.

[0224] Reference is now made to FIG. 25, which is a simplifiedillustration of wave propagation in a waveguide device of the type shownin FIG. 24, having a multi-mode interference coupler. It is seen that inthe multi-mode interference coupler, designated by reference numeral690, the waves interfere both constructive and destructively. Bysuitably selecting the dimensions of the multi-mode interference coupler690, as well known in the art, it can be ensured that constructiveinterference takes place at a number of locations 692 at the interface694 between the multi-mode interference coupler and the waveguide.

[0225] In accordance with a preferred embodiment of the presentinvention the waveguides 696 are constructed such that their entrances698 are aligned with locations 692, thereby maximizing the couplingefficiency between the multi-mode interference coupler 690 and thewaveguides 696.

[0226] In accordance with a preferred embodiment of the presentinvention, the input waveguide 700 to the multi-mode interferencecoupler 690 may be operative as an electro-absorption modulator, thefunctionality of which is well-known in the art.

[0227] Reference is now made to FIG. 26, which is a simplifiedillustration of wave propagation in a waveguide device having afree-space input coupler 710. The waveguide device may be identical tothat of FIGS. 24 and 25 in structure and function other than in that thedimensions of the free-space input coupler 710 are not such thatinterference occurs therewithin. Rather the light propagates freelytherethrough as shown to the interface 712 with waveguides 714. Inaccordance with a preferred embodiment of the present invention, theentrance 716 of each waveguide 714 is outwardly tapered, so as toenhance coupling efficiency.

[0228] As seen in FIG. 27, the waveguide devices described hereinabovewith reference to FIGS. 23, 24, 25 and 26 may be employed in opticalswitches both as selectably directable optical beam deflection devices730 at the input end 734 and as selectably directable receiving devices736 at the output end 738.

[0229] Reference is now made to FIG. 28, which is a simplifiedillustration of a monolithic device having both electronic and opticalfunctionality. The embodiment of FIG. 28 provides an active optical beamtransmission device comprising at least one substrate 750 having formedthereon a multiple layer integrated electronic circuit 752 and amultiplicity of electrically controlled waveguides 754.

[0230] In accordance with a preferred embodiment of the presentinvention, the waveguides 754 emit a selectably directable beam of lightor selectably receive a beam of light.

[0231] Reference is now made to FIG. 29, which is a simplifiedillustration of part of an optical switch including a monolithicplurality of selectably directable optical beam deflecting devices 760in accordance with one preferred embodiment of the present invention. Itis thus appreciated that in the embodiment of FIG. 29 all of the devices760 are formed on a single substrate 762. Each of devices 760 may besubstantially identical to the devices described hereinabove withreference to either of FIGS. 23 and 24.

[0232] In the embodiment of FIG. 29, the electronic connection pads 764are located adjacent each individual device 760.

[0233]FIG. 30 is a simplified illustration of part of an optical switchincluding a monolithic plurality of selectably directable optical beamdeflecting devices in accordance with another preferred embodiment ofthe present invention. It is similar to the embodiment of FIG. 29 otherthan in that the electronic connection pads 774 for all of theselectably directable optical beam deflecting devices 776 are alllocated adjacent the edges 778 of the common substrate 780.

[0234] Reference is now made to FIG. 31, which is a simplifiedillustration of part of an optical switch including a monolithicplurality of selectably directable optical beam deflecting devices inaccordance with yet another preferred embodiment of the presentinvention. Here, the electrical connection pads 794 are formed over partof the selectably directable optical beam deflecting waveguide devices796.

[0235] Reference is now made to FIG. 32, which is a simplifiedillustration of a waveguide device having a light coupler 800, of thetype described hereinabove with reference to any of FIGS. 24-26including an input waveguide 802 functioning as an electro-absorptionmodulator. The embodiment of FIG. 32 also includes a light detector 804providing a modulating output 806 to the electro-absorption modulatorwaveguide 802. Preferably, the light detector 804 receives a light inputfrom an information carrying modulated light source 808.

[0236] The electro-absorption modulator waveguide 802 of FIG. 32 mayserve as an electro-absorption modulator in the embodiments of FIGS.24-26. The light detector 804 is preferably monolithically formedtogether with the electro-absorption modulator waveguide 802 on the samesubstrate.

[0237] Reference is now made to FIG. 33, which is a simplifiedillustration of a beam deflector including a waveguide structure inaccordance with a preferred embodiment of the present invention. Thebeam deflector of FIG. 33 is characterized in that it includes aspherical output lens 820 which receives light from a cylindrical lens822. Cylindrical lens 822 is optically coupled to a multiplicity ofwaveguides 824 and is operative to direct the light received fromwaveguides 824 in a direction perpendicular to the plane of waveguides824. The spherical output lens 820 focuses the light received from thecylindrical lens 822.

[0238] Similarly to the structure described above with reference to FIG.23, the waveguides 824 receive light from a cylindrical lens 826 which,in turn, receives light from the end 828 of an optical fiber 830.Alternatively, the input structure of the waveguides 824 may be similarto that described above with reference to FIG. 24.

[0239] Reference is now made to FIG. 34, which is an illustration ofoperational parameters of a waveguide device having lens functionalityin accordance with a preferred embodiment of the present invention. FIG.34 indicates that by suitable selection of the electrical inputs to thewaveguide device of FIG. 33, the focusing functionality of the sphericallens 820 can be provided by the waveguides 824 and the spherical lens820 can be obviated.

[0240] Thus, it is appreciated that there is thus provided an opticalwaveguide-lens including a substrate having formed thereon amultiplicity of electrically controlled, phase-shifting waveguides andan electrical control signal source providing electrical signals to themultiplicity of waveguides to cause them to have a desired lensfunctionality.

[0241]FIG. 34 shows the phase shift produced by the electrical controlsignal as a function of the waveguide number. It is seen that a lensfunctionality, a tilt functionality and a combined lens and tiltfunctionality may be realized by suitable selection of electricalcontrol signals. It is appreciated that the lens functionality, takenalone, or in combination with the tilt functionality may be employed inany and all of the embodiments of the invention described herein.

[0242] The present invention also provides an optical switch comprisinga plurality of selectably directable optical beam deflecting devices anda plurality of optical beam receiving devices.

[0243] Reference is now made to FIG. 35, which is a simplifiedillustration of part of an optical cross-connect assembly constructedand operative in accordance with a preferred embodiment of the presentinvention. The embodiment of FIG. 35 is particularly characterized inthat it includes a plurality of selectably directable optical beamdeflecting devices 850, each comprising at least one substrate havingformed thereon a multiplicity of waveguides. Optical beam deflectingdevices of this type are described hereinabove with reference to FIGS.23 and 24.

[0244] The embodiment of FIG. 35 is also particularly characterized inthat it includes a plurality of optical beam receivers 852. Optical beamreceivers 852 may be optical fiber ends, as seen in FIG. 35. The opticalfibers may be single mode or multi-mode fibers and their ends may havesmall numerical apertures. Alternatively, optical beam receivers 852 maybe light detectors or selectably directable light receivers, asdescribed hereinabove with reference to FIG. 27.

[0245] In the embodiment of FIG. 35, at an input side 854, a pluralityof selectably directable optical beam deflecting devices 850 isarranged, each to receive light from a suitably positioned optical fiberend 856. It is noted that devices 850 are mounted on a substrate 858,such as a multi-layer ceramic substrate, onto which are also mountedcontrol electronics 860.

[0246] Light coupling between optical fiber ends 856 and beam deflectiondevices 850 may be achieved using a microlens array 862, as shown. Themicrolens array 862 may comprise a combination of cylindrical lensesarranged in two perpendicular directions. The microlens array 862provides focusing in two mutually perpendicular directions withdifferent optical power. Where devices 850 are similar to thosedescribed in FIG. 23, the microlens array 862 provides output beamswhich are collimated in a direction parallel to the plane of the devices850. Where devices 850 are similar to those described in FIG. 24, themicrolens array 862 provides output beams which are focused in adirection parallel to the plane of the devices 850.

[0247] Although a single row of cylindrical lenses is shown in FIG. 35,it is appreciated that a double row of cylindrical lenses mayalternatively be employed.

[0248] Alternatively, the microlens array 862 may be obviated andindividual lenses may be formed or mounted onto the optical fiber ends856.

[0249] Downstream of the plurality of selectably directable optical beamdeflecting devices 850 there is provided one or more cylindrical lenses864 which have essentially the same functionality as that provided bycylindrical lens 822 in the embodiment of FIG. 33. A spherical lens 866receives light from the one or more cylindrical lenses 864 and has thefunctionality of spherical lens 820 in the embodiment of FIG. 33.Similarly to spherical lens 820, it may be obviated in a case where theplurality of selectably directable optical beam deflecting devices 850are provided with a lens functionality.

[0250] It is appreciated that the input side 854 may function as anoutput side rather than an input side. In such a case, the structures,such as optical fiber ends, functioning as light receivers 852 mayfunction instead as light transmitters. The light transmitters may bestatic or directable.

[0251] Reference is now made to FIG. 36, which is a simplifiedillustration of an optical cross-connect assembly constructed andoperative in accordance with another preferred embodiment of the presentinvention. The optical cross-connect assembly of FIG. 36 is particularlycharacterized in that it includes a plurality of monolithic pluralities870 of selectably directable optical beam deflecting devices 872, aswell as a plurality of optical beam receiving devices 874. Theselectably directable optical beam deflecting devices 872 may be any ofthe devices described herein with reference to FIGS. 23-34. Themonolithic pluralities 870 may be any of the structures describedhereinabove with reference to FIG. 35.

[0252] In accordance with a preferred embodiment of the presentinvention, the plurality of monolithic pluralities 870 of beamdeflecting devices 872 are arranged generally parallel to one anotheralong an axis 876 perpendicular to a plane in which selectabledeflection of a light beam is produced thereby, which is the plane ofeach of the plurality of monolithic pluralities 870.

[0253] A focusing lens 878 receives light from the plurality ofmonolithic pluralities 870 of beam deflecting devices 872 and focuses itonto the light receiving devices 874. The lens 878 may be one or morelenses and may have the functionality of lens 820 in the embodiment ofFIG. 33. As such, it may be obviated by inclusion of lens functionalityin the plurality of monolithic pluralities 870 of beam deflectingdevices 872.

[0254] It is appreciated that the plurality of monolithic pluralities870 of beam deflecting devices 872 and lens 878 may alternativelyfunction as light receivers rather than a light transmitter. In such acase, the structures, such as optical fiber ends, functioning as lightreceivers 874 may function instead as light transmitters. The lighttransmitters may be static or directable.

[0255] Reference is now made to FIG. 37, which is a simplifiedillustration of an optical cross-connect assembly constructed andoperative in accordance with yet another preferred embodiment of thepresent invention. The optical cross-connect assembly of FIG. 37 isparticularly characterized in that it includes a plurality of monolithicpluralities 880 of selectably directable optical beam deflecting devices882, as well as a plurality of optical beam receiving devices 884. Theselectably directable optical beam deflecting devices 882 may be any ofthe devices described herein with reference to FIGS. 23-34. Themonolithic pluralities 880 may be any of the structures describedhereinabove with reference to FIG. 35.

[0256] Here the plurality of monolithic pluralities 880 of beamdeflecting devices 882 are arranged generally distributed along a curve886 extending in a plane perpendicular to a plane in which selectabledeflection of a light beam is produced thereby, which is the plane ofeach of the plurality of monolithic pluralities 880.

[0257] A focusing lens 888 receives light from the plurality ofmonolithic pluralities 880 of beam deflecting devices 882 and focuses itonto the light receiving devices 884. The lens 888 may be one or morelenses and may have the functionality of lens 820 in the embodiment ofFIG. 33. As such, it may be obviated by inclusion of lens functionalityin the plurality of monolithic pluralities 880 of beam deflectingdevices 882.

[0258] It is appreciated that the plurality of monolithic pluralities880 of beam deflecting devices 882 and lens 888 may alternativelyfunction as light receivers rather than a light transmitter. In such acase, the structures, such as optical fiber ends, functioning as lightreceivers 884 may function instead as light transmitters. The lighttransmitters may be static or directable.

[0259] Reference is now made to FIG. 38, which is a simplifiedillustration of an optical cross-connect assembly of the type shown inany of FIGS. 35-37 with feedback functionality. The embodiment of FIG.38 comprises an optical switch input end 900 which receives modulatedlight from a multiplicity of fibers 902 and selectably transmits themodulated light to a multiplicity of light receivers 904, such asoptical fiber ends. The switch input end 900 may be any suitable switchinput end of the type described herein with reference to any of FIGS.35, 36 & 37.

[0260] Signal pickup devices 906 receive at least one parameter of thesignals received by light receivers 904 and provide feedback inputsignals to a feedback processor 908. Output signals from the feedbackprocessor 908 are operative to govern at least one parameter of theoperation of the optical switch input end 900.

[0261] This feedback arrangement provides reduced crosstalk and enhancedtransmission efficiency.

[0262] The feedback input signals to feedback processor 908 mayrepresent received signal intensity and crosstalk. The parameters ofoperation of the optical switch input end 900 which are affected byoutput signals from the feedback processor include the phase shiftproduced by individual waveguides, the amount of rotation produced bythe polarization rotator, such as rotator 576 (FIG. 18) or rotator 590(FIG. 19). The feedback processor 908 effectively provides a feedbackconnection between the optical beam receiving devices and the opticalbeam deflecting devices.

[0263] It is appreciated that the feedback functionality need notnecessarily be automatic but rather may involve some operatorintervention.

[0264] Reference is now made to FIG. 39, which is a simplifiedillustration of an optical cross-connect assembly constructed andoperative in accordance with a preferred embodiment of the presentinvention. Here optical beam receiving devices 910 are configured toreceive light over a region 912 sufficiently large such that wavelengthdependencies of optical beam deflectors 914 do not substantially affectthe amount of light sensed by the receiving devices.

[0265] Reference is now made to FIG. 40, which is a simplifiedillustration of an optical cross-connect assembly constructed andoperative in accordance with a preferred embodiment of the presentinvention. Here a multiplicity of waveguides 920 are each operativesimultaneously to deflect a plurality of optical beams 922 and to directthem to a plurality of different receivers 924.

[0266] Reference is now made to FIG. 41, which is a simplifiedillustration of a waveguide filter constructed and operative inaccordance with a preferred embodiment of the present invention. Thewaveguide filter of FIG. 41 comprises a necked waveguide 930 having arelatively broad input end 932 which receives light and allowspropagation of multi-mode light waves therethrough. When the multi-modelight waves encounter a narrowed neck portion 934, the higher modesradiate outside the waveguide and only the modes which can propagatethrough the neck portion 934 pass therethrough to a relatively broadoutput end 936. This filter can be used to efficiently remove highermodes which can cause crosstalk.

[0267] It is appreciated that the structures of FIGS. 39, 40 and 41 maybe applied to any of the optical beam deflectors, optical beamreceivers, cross-connect assemblies and optical switches describedherein.

[0268] Reference is now made to FIG. 42, which is a simplifiedillustration of a monolithic optical cross-connect assembly constructedand operative in accordance with a preferred embodiment of the presentinvention. A plurality of selectably directable optical beam deflectingdevices 950 and a plurality of optical beam receiving devices 952 areall monolithically formed on the same substrate 954.

[0269] It will be appreciated by persons skilled in the art that thepresent invention is not limited to what has been particularly shown anddescribed hereinabove. Rather the scope of the present inventionincludes both combinations and subcombinations of various featuresdescribed hereinabove and shown in the drawings as well as modificationsthereto and variations thereof which would occur to a person skilled inthe art upon reading the description and which are not in the prior art.

1. A selectably directable optical beam deflecting device comprising: atleast one substrate having formed thereon a multiplicity of waveguides,each waveguide receiving light and emitting light, the totality of lightemitted by said multiplicity of waveguides producing at least oneselectably directable output beam; and at least one multiplexer applyingelectrical inputs to said at least one substrate for individuallycontrolling the light emitted by each of the multiplicity of waveguides,thereby governing the orientation of said selectably directable outputbeam.
 2. A selectably directable optical beam deflecting deviceaccording to claim 1 and wherein said at least one multiplexer is asequential phase controller which controls the phase of the lightemitted by each of the multiplicity of waveguides.
 3. A selectablydirectable optical beam deflecting device according to claim 1 andwherein said at least one multiplexer is a sequential intensitycontroller which controls the intensity of the light emitted by each ofthe multiplicity of waveguides.
 4. A selectably directable optical beamdeflecting device according to claim 1 and wherein said at least onesubstrate comprises a plurality of substrates, each having formedthereon a multiplicity of waveguides, each waveguide receiving light andemitting light and wherein said at least one multiplexer applieselectrical inputs to said plurality of substrates.
 5. A selectablydirectable optical beam deflecting device comprising: a plurality ofsubstrates, each having formed thereon a multiplicity of waveguides,each waveguide receiving light and emitting light, the totality of lightemitted by said multiplicity of waveguides producing at least oneselectably directable output beam.
 6. A selectably directable opticalbeam deflecting device comprising: at least one substrate having formedthereon a multiplicity of waveguides; and a microlens array receivinglight and coupling said received light to said multiplicity ofwaveguides.
 7. A selectably directable optical beam generating devicecomprising: a light source; at least one substrate having formed thereona multiplicity of waveguides; and a microlens array receiving light fromsaid light source and coupling said received light to said multiplicityof waveguides.
 8. An optical device according to claim 1 and whereinsaid selectably directable optical beam deflecting device provideswavelength division multiplexing functionality.
 9. An optical deviceaccording to claim 1 and having selectably directable beam deflectionfunctionality.
 10. An optical device according to claim 9 and whereinsaid multiplicity of waveguides comprises a multiplicity of polarizationindependent, electrically controlled waveguides, said optical devicealso comprising: a light receiver directing light into said multiplicityof waveguides.
 11. An optical device according to claim 10 and whereineach one of said multiplicity of polarization independent, electricallycontrolled waveguides comprises first and second phase shiftingwaveguide portions.
 12. An optical device according to claim 11 andwherein electric fields of different directions are applied to saidfirst and second phase shifting waveguide portions.
 13. An opticaldevice according to claim 11 and wherein each of said multiplicity ofpolarization independent electrically controlled waveguides comprisesfirst and second phase-shifting waveguide portions of respective firstand second lengths having respective first and second electric fields ofdifferent directions applied thereto.
 14. An optical device according toclaim 10 and wherein at least one of said multiplicity of polarizationindependent, electrically controlled waveguides comprises first andsecond phase shifting waveguide portions separated by a quarter-waveplate, whereby light from said first waveguide portion passes throughsaid quarter-wave plate prior to enter said second waveguide portion.15. An optical device according to claim 9 and wherein said multiplicityof waveguides comprises a multiplicity of electrically controlledwaveguides, said optical device also comprising: a light receiver fordirecting light into said multiplicity of waveguides, said lightreceiver comprising a selectable polarization rotator.
 16. An opticaldevice according to claim 9 and wherein said multiplicity of waveguidescomprises a multiplicity of electrically controlled waveguides, saidoptical device also comprising: a polarization rotator for rotating thepolarization of light passing through said multiplicity of electricallycontrolled waveguides by 90 degrees or an odd integer multiple thereof.17. An optical device according to claim 16 and wherein saidpolarization rotator operates by generating a magnetic field extendingparallel to longitudinal axes of said multiplicity of waveguides.
 18. Anoptical device according to claim 16 and wherein said selectablepolarization rotator is automatically operative to rotate thepolarization so as to provide an optimized light output from saidmultiplicity of waveguides.
 19. An optical device according to claim 18and wherein said selectable polarization rotator is responsive to anoutput of said multiplicity of waveguides.
 20. An optical deviceaccording to claim 18 and wherein said selectable polarization rotatoris responsive to the polarization of an input to said multiplicity ofwaveguides.
 21. An optical device according to claim 1 and havingselectably directable beam receiving functionality.
 22. An opticaldevice according to claim 21 and wherein said multiplicity of waveguidescomprises a multiplicity of polarization independent, electricallycontrolled waveguides, said optical device also comprising: a lightreceiver directing light into said multiplicity of waveguides.
 23. Anoptical device according to claim 22 and wherein each one of saidmultiplicity of polarization independent, electrically controlledwaveguides comprises first and second phase shifting waveguide portions.24. An optical device according to claim 23 and wherein electric fieldsof different directions are applied to said first and second phaseshifting waveguide portions.
 25. An optical device according to claim 23and wherein each of said multiplicity of polarization independentelectrically controlled waveguides comprises first and secondphase-shifting waveguide portions of respective first and second lengthshaving respective first and second electric fields of differentdirections applied thereto.
 26. An optical device according to claim 22and wherein at least one of said multiplicity of polarizationindependent, electrically controlled waveguides comprises first andsecond phase-shifting waveguide portions separated by a quarter-waveplate, whereby light from said first waveguide portion passes throughsaid quarter-wave plate prior to entering said second waveguide portion.27. An optical device according to claim 21 and wherein saidmultiplicity of waveguides comprises a multiplicity of electricallycontrolled waveguides, said optical device also comprising: a lightreceiver for directing light into said multiplicity of waveguides, saidlight receiver comprising a selectable polarization rotator.
 28. Anoptical device according to claim 21 and wherein said multiplicity ofwaveguides comprises a multiplicity of electrically controlledwaveguides, said optical device also comprising: a polarization rotatorfor rotating the polarization of light passing through said multiplicityof electrically controlled waveguides by 90 degrees or an odd integermultiple thereof.
 29. An optical device according to claim 28 andwherein said polarization rotator operates by generating a magneticfield extending parallel to longitudinal axes of said multiplicity ofwaveguides.
 30. An optical device according to claim 28 and wherein saidselectable polarization rotator is automatically operative to rotate thepolarization so as to provide an optimized light output from saidmultiplicity of waveguides.
 31. An optical device according to claim 30and wherein said selectable polarization rotator is responsive to anoutput of said multiplicity of waveguides.
 32. An optical deviceaccording to claim 30 and wherein said selectable polarization rotatoris responsive to the polarization of an input to said multiplicity ofwaveguides.
 33. An optical device according to claim 9 and wherein saidselectably directable functionality is realized by means ofphase-shifting.
 34. An optical device according to claim 21 and whereinsaid selectably directable functionality is realized by means ofphase-shifting.
 35. A selectably directable optical beam generatingdevice according to claim 1 and also comprising: a light source.
 36. Aselectably directable optical beam generating device according to claim35 and wherein said at least one multiplexes is a phase controller whichcontrols the phase of the light emitted by each of the multiplicity ofwaveguides.
 37. A selectably directable optical beam generating deviceaccording to claim 35 and wherein said at least one multiplexer is anintensity controller controls the intensity of the light emitted by eachof the multiplicity of waveguides.
 38. A selectably directable opticalbeam generating device according to claim 35 and wherein said at leastone substrate comprises a plurality of substrates, each having formedthereon a multiplicity of waveguides, each waveguide receiving light andemitting light and wherein said at least one multiplexes applieselectrical inputs to said plurality of substrates.
 39. A selectablydirectable optical beam generating device according to claim 35 andwherein said light source comprises a laser formed on said at least onesubstrate.
 40. An optical device according to claim 1 and wherein saidmultiplicity of waveguides comprise a multiplicity of electricallycontrolled waveguides and wherein said optical device also comprises: alight receiver directing light into said multiplicity of waveguides andincluding polarization maintaining optical fibers.
 41. A selectablydirectable optical beam deflecting device according to claim 1 and alsocomprising: a light receiver coupling light to said multiplicity ofwaveguides at first ends thereof and wherein said multiplicity ofwaveguides are outwardly tapered at said first ends thereof.
 42. Aselectably directable optical beam deflecting device according to claim1 and comprising: a light receiver directing light into saidmultiplicity of waveguides, said light receiver comprising a cylindricallens.
 43. A selectably directable optical beam deflecting deviceaccording to claim 1 and comprising: a light receiver directing lightinto said multiplicity of waveguides, said light receiver comprising amulti-mode interference coupler.
 44. A selectably directable opticalbeam deflecting device according to claim 1 and comprising: a lightreceiver directing light into said multiplicity of waveguides, saidlight receiver comprising a planar wave guide.
 45. A selectablydirectable optical beam deflecting device according to claim 44 andwherein said multiplicity of waveguides have first ends which abut saidplanar waveguide, said first ends being tapered outwardly.
 46. Aselectably directable optical beam deflecting device according to claim44 and wherein said planar waveguide comprises a light receivingwaveguide.
 47. A selectably directable optical beam deflecting deviceaccording to claim 46 and wherein said light receiving waveguideincludes a light receiving end which is outwardly tapered.
 48. Aselectably directable optical beam deflecting device according to claim46 and wherein said light receiving waveguide comprises a modulator. 49.A selectably directable optical beam deflecting device according toclaim 48 and wherein said modulator receives a modulating input from alight detector monolithically formed therewith on said at least onesubstrate.
 50. An optical device according to claim 1 and wherein saidmultiplicity of waveguides is controllable so as to selectably providemultiple selectably directed output beams.
 51. An optical deviceaccording to claim 1 and also comprising a waveguide filter including: anecked waveguide having a relatively broad input end which receiveslight and allows propagation of multi-mode light waves therethrough; anarrowed neck portion at which higher modes radiate outside thewaveguide and only the modes which can propagate therethrough passtherethrough; and a relatively broad output end.
 52. An optical deviceaccording to claim 1 and wherein said substrate comprises galliumarsenide.
 53. An active optical beam transmission device according toclaim 1 and also comprising a multiple layer integrated electroniccircuit formed on said substrate.
 54. An active optical beamtransmission device according to claim 53 and wherein said multiplicityof waveguides emit a selectably directable beam of light.
 55. An activeoptical beam transmission device according to claim 53 and wherein saidmultiplicity of waveguides selectably receive a beam of light.
 56. Anoptical device according to claim 1 wherein said multiplicity ofwaveguides comprises a multiplicity of electrically controlledwaveguides and wherein said device also comprises: overlying saidmultiplicity of waveguides, a multiplicity of electrical contacts, eachcontact providing an electrical connection to at least one of themultiplicity of electrically controlled waveguides.
 57. An opticaldevice according to claim 1 wherein said multiplicity of waveguidescomprises a plurality of waveguide assemblies, each including amultiplicity of electrically controlled waveguides and wherein saiddevice also comprises: overlying each of said waveguide assemblies, amultiplicity of electrical contacts, each contact providing anelectrical connection to at least one of the multiplicity ofelectrically controlled waveguides in said assembly.
 58. An opticalwaveguide-lens device according to claim 1 and wherein said multiplicityof waveguides comprises a multiplicity of electrically controlled,phase-shifting waveguides and wherein said device also comprises: anelectrical control signal source providing electrical signals to saidmultiplicity of waveguides to cause them to have a desired lensfunctionality.
 59. Apparatus according to claim 1 and also comprising anelectrical control signal source providing electrical signals to saidmultiplicity of waveguides to cause them to have a desired lensfunctionality.
 60. A selectably directable optical beam deflectingdevice according to claim 1 and wherein: said multiplicity of waveguidescomprise a multiplicity of phase-shifting waveguides; said at least onesubstrate comprises multiple mutually insulated conductor layersincluding a multiplicity of conductors, at least some of which areconnected to said waveguides by vias, and wherein said device alsocomprises: a light receiver directing light into said multiplicity ofwaveguides.